2 * Copyright (c) 2009, Microsoft Corporation.
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms and conditions of the GNU General Public License,
6 * version 2, as published by the Free Software Foundation.
8 * This program is distributed in the hope it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * You should have received a copy of the GNU General Public License along with
14 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
15 * Place - Suite 330, Boston, MA 02111-1307 USA.
18 * Haiyang Zhang <haiyangz@microsoft.com>
19 * Hank Janssen <hjanssen@microsoft.com>
21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23 #include <linux/kernel.h>
24 #include <linux/sched.h>
25 #include <linux/wait.h>
27 #include <linux/slab.h>
28 #include <linux/list.h>
29 #include <linux/module.h>
30 #include <linux/completion.h>
31 #include <linux/hyperv.h>
33 #include "hyperv_vmbus.h"
35 static void init_vp_index(struct vmbus_channel *channel,
36 const uuid_le *type_guid);
39 * vmbus_prep_negotiate_resp() - Create default response for Hyper-V Negotiate message
40 * @icmsghdrp: Pointer to msg header structure
41 * @icmsg_negotiate: Pointer to negotiate message structure
42 * @buf: Raw buffer channel data
44 * @icmsghdrp is of type &struct icmsg_hdr.
45 * @negop is of type &struct icmsg_negotiate.
46 * Set up and fill in default negotiate response message.
48 * The fw_version specifies the framework version that
49 * we can support and srv_version specifies the service
50 * version we can support.
52 * Mainly used by Hyper-V drivers.
54 bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
55 struct icmsg_negotiate *negop, u8 *buf,
56 int fw_version, int srv_version)
58 int icframe_major, icframe_minor;
59 int icmsg_major, icmsg_minor;
60 int fw_major, fw_minor;
61 int srv_major, srv_minor;
63 bool found_match = false;
65 icmsghdrp->icmsgsize = 0x10;
66 fw_major = (fw_version >> 16);
67 fw_minor = (fw_version & 0xFFFF);
69 srv_major = (srv_version >> 16);
70 srv_minor = (srv_version & 0xFFFF);
72 negop = (struct icmsg_negotiate *)&buf[
73 sizeof(struct vmbuspipe_hdr) +
74 sizeof(struct icmsg_hdr)];
76 icframe_major = negop->icframe_vercnt;
79 icmsg_major = negop->icmsg_vercnt;
83 * Select the framework version number we will
87 for (i = 0; i < negop->icframe_vercnt; i++) {
88 if ((negop->icversion_data[i].major == fw_major) &&
89 (negop->icversion_data[i].minor == fw_minor)) {
90 icframe_major = negop->icversion_data[i].major;
91 icframe_minor = negop->icversion_data[i].minor;
101 for (i = negop->icframe_vercnt;
102 (i < negop->icframe_vercnt + negop->icmsg_vercnt); i++) {
103 if ((negop->icversion_data[i].major == srv_major) &&
104 (negop->icversion_data[i].minor == srv_minor)) {
105 icmsg_major = negop->icversion_data[i].major;
106 icmsg_minor = negop->icversion_data[i].minor;
112 * Respond with the framework and service
113 * version numbers we can support.
118 negop->icframe_vercnt = 0;
119 negop->icmsg_vercnt = 0;
121 negop->icframe_vercnt = 1;
122 negop->icmsg_vercnt = 1;
125 negop->icversion_data[0].major = icframe_major;
126 negop->icversion_data[0].minor = icframe_minor;
127 negop->icversion_data[1].major = icmsg_major;
128 negop->icversion_data[1].minor = icmsg_minor;
132 EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);
135 * alloc_channel - Allocate and initialize a vmbus channel object
137 static struct vmbus_channel *alloc_channel(void)
139 static atomic_t chan_num = ATOMIC_INIT(0);
140 struct vmbus_channel *channel;
142 channel = kzalloc(sizeof(*channel), GFP_ATOMIC);
146 channel->id = atomic_inc_return(&chan_num);
147 spin_lock_init(&channel->inbound_lock);
148 spin_lock_init(&channel->lock);
150 INIT_LIST_HEAD(&channel->sc_list);
151 INIT_LIST_HEAD(&channel->percpu_list);
157 * free_channel - Release the resources used by the vmbus channel object
159 static void free_channel(struct vmbus_channel *channel)
164 static void percpu_channel_enq(void *arg)
166 struct vmbus_channel *channel = arg;
167 int cpu = smp_processor_id();
169 list_add_tail(&channel->percpu_list, &hv_context.percpu_list[cpu]);
172 static void percpu_channel_deq(void *arg)
174 struct vmbus_channel *channel = arg;
176 list_del(&channel->percpu_list);
180 void hv_process_channel_removal(struct vmbus_channel *channel, u32 relid)
182 struct vmbus_channel_relid_released msg;
184 struct vmbus_channel *primary_channel;
186 memset(&msg, 0, sizeof(struct vmbus_channel_relid_released));
187 msg.child_relid = relid;
188 msg.header.msgtype = CHANNELMSG_RELID_RELEASED;
189 vmbus_post_msg(&msg, sizeof(struct vmbus_channel_relid_released));
194 BUG_ON(!channel->rescind);
196 if (channel->target_cpu != get_cpu()) {
198 smp_call_function_single(channel->target_cpu,
199 percpu_channel_deq, channel, true);
201 percpu_channel_deq(channel);
205 if (channel->primary_channel == NULL) {
206 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
207 list_del(&channel->listentry);
208 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
210 primary_channel = channel;
212 primary_channel = channel->primary_channel;
213 spin_lock_irqsave(&primary_channel->lock, flags);
214 list_del(&channel->sc_list);
215 primary_channel->num_sc--;
216 spin_unlock_irqrestore(&primary_channel->lock, flags);
220 * We need to free the bit for init_vp_index() to work in the case
221 * of sub-channel, when we reload drivers like hv_netvsc.
223 cpumask_clear_cpu(channel->target_cpu,
224 &primary_channel->alloced_cpus_in_node);
226 free_channel(channel);
229 void vmbus_free_channels(void)
231 struct vmbus_channel *channel, *tmp;
233 list_for_each_entry_safe(channel, tmp, &vmbus_connection.chn_list,
235 /* hv_process_channel_removal() needs this */
236 channel->rescind = true;
238 vmbus_device_unregister(channel->device_obj);
243 * vmbus_process_offer - Process the offer by creating a channel/device
244 * associated with this offer
246 static void vmbus_process_offer(struct vmbus_channel *newchannel)
248 struct vmbus_channel *channel;
252 /* Make sure this is a new offer */
253 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
255 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
256 if (!uuid_le_cmp(channel->offermsg.offer.if_type,
257 newchannel->offermsg.offer.if_type) &&
258 !uuid_le_cmp(channel->offermsg.offer.if_instance,
259 newchannel->offermsg.offer.if_instance)) {
266 list_add_tail(&newchannel->listentry,
267 &vmbus_connection.chn_list);
269 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
273 * Check to see if this is a sub-channel.
275 if (newchannel->offermsg.offer.sub_channel_index != 0) {
277 * Process the sub-channel.
279 newchannel->primary_channel = channel;
280 spin_lock_irqsave(&channel->lock, flags);
281 list_add_tail(&newchannel->sc_list, &channel->sc_list);
283 spin_unlock_irqrestore(&channel->lock, flags);
288 init_vp_index(newchannel, &newchannel->offermsg.offer.if_type);
290 if (newchannel->target_cpu != get_cpu()) {
292 smp_call_function_single(newchannel->target_cpu,
296 percpu_channel_enq(newchannel);
301 * This state is used to indicate a successful open
302 * so that when we do close the channel normally, we
303 * can cleanup properly
305 newchannel->state = CHANNEL_OPEN_STATE;
308 if (channel->sc_creation_callback != NULL)
309 channel->sc_creation_callback(newchannel);
314 * Start the process of binding this offer to the driver
315 * We need to set the DeviceObject field before calling
316 * vmbus_child_dev_add()
318 newchannel->device_obj = vmbus_device_create(
319 &newchannel->offermsg.offer.if_type,
320 &newchannel->offermsg.offer.if_instance,
322 if (!newchannel->device_obj)
326 * Add the new device to the bus. This will kick off device-driver
327 * binding which eventually invokes the device driver's AddDevice()
330 if (vmbus_device_register(newchannel->device_obj) != 0) {
331 pr_err("unable to add child device object (relid %d)\n",
332 newchannel->offermsg.child_relid);
333 kfree(newchannel->device_obj);
339 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
340 list_del(&newchannel->listentry);
341 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
343 if (newchannel->target_cpu != get_cpu()) {
345 smp_call_function_single(newchannel->target_cpu,
346 percpu_channel_deq, newchannel, true);
348 percpu_channel_deq(newchannel);
353 free_channel(newchannel);
365 * This is an array of device_ids (device types) that are performance critical.
366 * We attempt to distribute the interrupt load for these devices across
367 * all available CPUs.
369 static const struct hv_vmbus_device_id hp_devs[] = {
376 /* NetworkDirect Guest RDMA */
382 * We use this state to statically distribute the channel interrupt load.
384 static int next_numa_node_id;
387 * Starting with Win8, we can statically distribute the incoming
388 * channel interrupt load by binding a channel to VCPU.
389 * We do this in a hierarchical fashion:
390 * First distribute the primary channels across available NUMA nodes
391 * and then distribute the subchannels amongst the CPUs in the NUMA
392 * node assigned to the primary channel.
394 * For pre-win8 hosts or non-performance critical channels we assign the
395 * first CPU in the first NUMA node.
397 static void init_vp_index(struct vmbus_channel *channel, const uuid_le *type_guid)
401 bool perf_chn = false;
402 struct vmbus_channel *primary = channel->primary_channel;
404 struct cpumask available_mask;
405 struct cpumask *alloced_mask;
407 for (i = IDE; i < MAX_PERF_CHN; i++) {
408 if (!memcmp(type_guid->b, hp_devs[i].guid,
414 if ((vmbus_proto_version == VERSION_WS2008) ||
415 (vmbus_proto_version == VERSION_WIN7) || (!perf_chn)) {
417 * Prior to win8, all channel interrupts are
418 * delivered on cpu 0.
419 * Also if the channel is not a performance critical
420 * channel, bind it to cpu 0.
422 channel->numa_node = 0;
423 channel->target_cpu = 0;
424 channel->target_vp = hv_context.vp_index[0];
429 * We distribute primary channels evenly across all the available
430 * NUMA nodes and within the assigned NUMA node we will assign the
431 * first available CPU to the primary channel.
432 * The sub-channels will be assigned to the CPUs available in the
437 next_node = next_numa_node_id++;
438 if (next_node == nr_node_ids)
439 next_node = next_numa_node_id = 0;
440 if (cpumask_empty(cpumask_of_node(next_node)))
444 channel->numa_node = next_node;
447 alloced_mask = &hv_context.hv_numa_map[primary->numa_node];
449 if (cpumask_weight(alloced_mask) ==
450 cpumask_weight(cpumask_of_node(primary->numa_node))) {
452 * We have cycled through all the CPUs in the node;
453 * reset the alloced map.
455 cpumask_clear(alloced_mask);
458 cpumask_xor(&available_mask, alloced_mask,
459 cpumask_of_node(primary->numa_node));
464 * Normally Hyper-V host doesn't create more subchannels than there
465 * are VCPUs on the node but it is possible when not all present VCPUs
466 * on the node are initialized by guest. Clear the alloced_cpus_in_node
469 if (cpumask_equal(&primary->alloced_cpus_in_node,
470 cpumask_of_node(primary->numa_node)))
471 cpumask_clear(&primary->alloced_cpus_in_node);
474 cur_cpu = cpumask_next(cur_cpu, &available_mask);
475 if (cur_cpu >= nr_cpu_ids) {
477 cpumask_copy(&available_mask,
478 cpumask_of_node(primary->numa_node));
483 * NOTE: in the case of sub-channel, we clear the sub-channel
484 * related bit(s) in primary->alloced_cpus_in_node in
485 * hv_process_channel_removal(), so when we reload drivers
486 * like hv_netvsc in SMP guest, here we're able to re-allocate
487 * bit from primary->alloced_cpus_in_node.
489 if (!cpumask_test_cpu(cur_cpu,
490 &primary->alloced_cpus_in_node)) {
491 cpumask_set_cpu(cur_cpu,
492 &primary->alloced_cpus_in_node);
493 cpumask_set_cpu(cur_cpu, alloced_mask);
498 channel->target_cpu = cur_cpu;
499 channel->target_vp = hv_context.vp_index[cur_cpu];
503 * vmbus_unload_response - Handler for the unload response.
505 static void vmbus_unload_response(struct vmbus_channel_message_header *hdr)
508 * This is a global event; just wakeup the waiting thread.
509 * Once we successfully unload, we can cleanup the monitor state.
511 complete(&vmbus_connection.unload_event);
514 void vmbus_initiate_unload(void)
516 struct vmbus_channel_message_header hdr;
518 /* Pre-Win2012R2 hosts don't support reconnect */
519 if (vmbus_proto_version < VERSION_WIN8_1)
522 init_completion(&vmbus_connection.unload_event);
523 memset(&hdr, 0, sizeof(struct vmbus_channel_message_header));
524 hdr.msgtype = CHANNELMSG_UNLOAD;
525 vmbus_post_msg(&hdr, sizeof(struct vmbus_channel_message_header));
527 wait_for_completion(&vmbus_connection.unload_event);
531 * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
534 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
536 struct vmbus_channel_offer_channel *offer;
537 struct vmbus_channel *newchannel;
539 offer = (struct vmbus_channel_offer_channel *)hdr;
541 /* Allocate the channel object and save this offer. */
542 newchannel = alloc_channel();
544 pr_err("Unable to allocate channel object\n");
549 * By default we setup state to enable batched
550 * reading. A specific service can choose to
551 * disable this prior to opening the channel.
553 newchannel->batched_reading = true;
556 * Setup state for signalling the host.
558 newchannel->sig_event = (struct hv_input_signal_event *)
559 (ALIGN((unsigned long)
560 &newchannel->sig_buf,
561 HV_HYPERCALL_PARAM_ALIGN));
563 newchannel->sig_event->connectionid.asu32 = 0;
564 newchannel->sig_event->connectionid.u.id = VMBUS_EVENT_CONNECTION_ID;
565 newchannel->sig_event->flag_number = 0;
566 newchannel->sig_event->rsvdz = 0;
568 if (vmbus_proto_version != VERSION_WS2008) {
569 newchannel->is_dedicated_interrupt =
570 (offer->is_dedicated_interrupt != 0);
571 newchannel->sig_event->connectionid.u.id =
572 offer->connection_id;
575 memcpy(&newchannel->offermsg, offer,
576 sizeof(struct vmbus_channel_offer_channel));
577 newchannel->monitor_grp = (u8)offer->monitorid / 32;
578 newchannel->monitor_bit = (u8)offer->monitorid % 32;
580 vmbus_process_offer(newchannel);
584 * vmbus_onoffer_rescind - Rescind offer handler.
586 * We queue a work item to process this offer synchronously
588 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
590 struct vmbus_channel_rescind_offer *rescind;
591 struct vmbus_channel *channel;
595 rescind = (struct vmbus_channel_rescind_offer *)hdr;
596 channel = relid2channel(rescind->child_relid);
598 if (channel == NULL) {
599 hv_process_channel_removal(NULL, rescind->child_relid);
603 spin_lock_irqsave(&channel->lock, flags);
604 channel->rescind = true;
605 spin_unlock_irqrestore(&channel->lock, flags);
607 if (channel->device_obj) {
609 * We will have to unregister this device from the
612 dev = get_device(&channel->device_obj->device);
614 vmbus_device_unregister(channel->device_obj);
618 hv_process_channel_removal(channel,
619 channel->offermsg.child_relid);
624 * vmbus_onoffers_delivered -
625 * This is invoked when all offers have been delivered.
627 * Nothing to do here.
629 static void vmbus_onoffers_delivered(
630 struct vmbus_channel_message_header *hdr)
635 * vmbus_onopen_result - Open result handler.
637 * This is invoked when we received a response to our channel open request.
638 * Find the matching request, copy the response and signal the requesting
641 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
643 struct vmbus_channel_open_result *result;
644 struct vmbus_channel_msginfo *msginfo;
645 struct vmbus_channel_message_header *requestheader;
646 struct vmbus_channel_open_channel *openmsg;
649 result = (struct vmbus_channel_open_result *)hdr;
652 * Find the open msg, copy the result and signal/unblock the wait event
654 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
656 list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
659 (struct vmbus_channel_message_header *)msginfo->msg;
661 if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
663 (struct vmbus_channel_open_channel *)msginfo->msg;
664 if (openmsg->child_relid == result->child_relid &&
665 openmsg->openid == result->openid) {
666 memcpy(&msginfo->response.open_result,
669 struct vmbus_channel_open_result));
670 complete(&msginfo->waitevent);
675 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
679 * vmbus_ongpadl_created - GPADL created handler.
681 * This is invoked when we received a response to our gpadl create request.
682 * Find the matching request, copy the response and signal the requesting
685 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
687 struct vmbus_channel_gpadl_created *gpadlcreated;
688 struct vmbus_channel_msginfo *msginfo;
689 struct vmbus_channel_message_header *requestheader;
690 struct vmbus_channel_gpadl_header *gpadlheader;
693 gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
696 * Find the establish msg, copy the result and signal/unblock the wait
699 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
701 list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
704 (struct vmbus_channel_message_header *)msginfo->msg;
706 if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
708 (struct vmbus_channel_gpadl_header *)requestheader;
710 if ((gpadlcreated->child_relid ==
711 gpadlheader->child_relid) &&
712 (gpadlcreated->gpadl == gpadlheader->gpadl)) {
713 memcpy(&msginfo->response.gpadl_created,
716 struct vmbus_channel_gpadl_created));
717 complete(&msginfo->waitevent);
722 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
726 * vmbus_ongpadl_torndown - GPADL torndown handler.
728 * This is invoked when we received a response to our gpadl teardown request.
729 * Find the matching request, copy the response and signal the requesting
732 static void vmbus_ongpadl_torndown(
733 struct vmbus_channel_message_header *hdr)
735 struct vmbus_channel_gpadl_torndown *gpadl_torndown;
736 struct vmbus_channel_msginfo *msginfo;
737 struct vmbus_channel_message_header *requestheader;
738 struct vmbus_channel_gpadl_teardown *gpadl_teardown;
741 gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
744 * Find the open msg, copy the result and signal/unblock the wait event
746 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
748 list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
751 (struct vmbus_channel_message_header *)msginfo->msg;
753 if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
755 (struct vmbus_channel_gpadl_teardown *)requestheader;
757 if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
758 memcpy(&msginfo->response.gpadl_torndown,
761 struct vmbus_channel_gpadl_torndown));
762 complete(&msginfo->waitevent);
767 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
771 * vmbus_onversion_response - Version response handler
773 * This is invoked when we received a response to our initiate contact request.
774 * Find the matching request, copy the response and signal the requesting
777 static void vmbus_onversion_response(
778 struct vmbus_channel_message_header *hdr)
780 struct vmbus_channel_msginfo *msginfo;
781 struct vmbus_channel_message_header *requestheader;
782 struct vmbus_channel_version_response *version_response;
785 version_response = (struct vmbus_channel_version_response *)hdr;
786 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
788 list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
791 (struct vmbus_channel_message_header *)msginfo->msg;
793 if (requestheader->msgtype ==
794 CHANNELMSG_INITIATE_CONTACT) {
795 memcpy(&msginfo->response.version_response,
797 sizeof(struct vmbus_channel_version_response));
798 complete(&msginfo->waitevent);
801 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
804 /* Channel message dispatch table */
805 struct vmbus_channel_message_table_entry
806 channel_message_table[CHANNELMSG_COUNT] = {
807 {CHANNELMSG_INVALID, 0, NULL},
808 {CHANNELMSG_OFFERCHANNEL, 0, vmbus_onoffer},
809 {CHANNELMSG_RESCIND_CHANNELOFFER, 0, vmbus_onoffer_rescind},
810 {CHANNELMSG_REQUESTOFFERS, 0, NULL},
811 {CHANNELMSG_ALLOFFERS_DELIVERED, 1, vmbus_onoffers_delivered},
812 {CHANNELMSG_OPENCHANNEL, 0, NULL},
813 {CHANNELMSG_OPENCHANNEL_RESULT, 1, vmbus_onopen_result},
814 {CHANNELMSG_CLOSECHANNEL, 0, NULL},
815 {CHANNELMSG_GPADL_HEADER, 0, NULL},
816 {CHANNELMSG_GPADL_BODY, 0, NULL},
817 {CHANNELMSG_GPADL_CREATED, 1, vmbus_ongpadl_created},
818 {CHANNELMSG_GPADL_TEARDOWN, 0, NULL},
819 {CHANNELMSG_GPADL_TORNDOWN, 1, vmbus_ongpadl_torndown},
820 {CHANNELMSG_RELID_RELEASED, 0, NULL},
821 {CHANNELMSG_INITIATE_CONTACT, 0, NULL},
822 {CHANNELMSG_VERSION_RESPONSE, 1, vmbus_onversion_response},
823 {CHANNELMSG_UNLOAD, 0, NULL},
824 {CHANNELMSG_UNLOAD_RESPONSE, 1, vmbus_unload_response},
828 * vmbus_onmessage - Handler for channel protocol messages.
830 * This is invoked in the vmbus worker thread context.
832 void vmbus_onmessage(void *context)
834 struct hv_message *msg = context;
835 struct vmbus_channel_message_header *hdr;
838 hdr = (struct vmbus_channel_message_header *)msg->u.payload;
839 size = msg->header.payload_size;
841 if (hdr->msgtype >= CHANNELMSG_COUNT) {
842 pr_err("Received invalid channel message type %d size %d\n",
844 print_hex_dump_bytes("", DUMP_PREFIX_NONE,
845 (unsigned char *)msg->u.payload, size);
849 if (channel_message_table[hdr->msgtype].message_handler)
850 channel_message_table[hdr->msgtype].message_handler(hdr);
852 pr_err("Unhandled channel message type %d\n", hdr->msgtype);
856 * vmbus_request_offers - Send a request to get all our pending offers.
858 int vmbus_request_offers(void)
860 struct vmbus_channel_message_header *msg;
861 struct vmbus_channel_msginfo *msginfo;
864 msginfo = kmalloc(sizeof(*msginfo) +
865 sizeof(struct vmbus_channel_message_header),
870 msg = (struct vmbus_channel_message_header *)msginfo->msg;
872 msg->msgtype = CHANNELMSG_REQUESTOFFERS;
875 ret = vmbus_post_msg(msg,
876 sizeof(struct vmbus_channel_message_header));
878 pr_err("Unable to request offers - %d\n", ret);
890 * Retrieve the (sub) channel on which to send an outgoing request.
891 * When a primary channel has multiple sub-channels, we try to
892 * distribute the load equally amongst all available channels.
894 struct vmbus_channel *vmbus_get_outgoing_channel(struct vmbus_channel *primary)
896 struct list_head *cur, *tmp;
898 struct vmbus_channel *cur_channel;
899 struct vmbus_channel *outgoing_channel = primary;
903 if (list_empty(&primary->sc_list))
904 return outgoing_channel;
906 next_channel = primary->next_oc++;
908 if (next_channel > (primary->num_sc)) {
909 primary->next_oc = 0;
910 return outgoing_channel;
913 cur_cpu = hv_context.vp_index[get_cpu()];
915 list_for_each_safe(cur, tmp, &primary->sc_list) {
916 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
917 if (cur_channel->state != CHANNEL_OPENED_STATE)
920 if (cur_channel->target_vp == cur_cpu)
923 if (i == next_channel)
929 return outgoing_channel;
931 EXPORT_SYMBOL_GPL(vmbus_get_outgoing_channel);
933 static void invoke_sc_cb(struct vmbus_channel *primary_channel)
935 struct list_head *cur, *tmp;
936 struct vmbus_channel *cur_channel;
938 if (primary_channel->sc_creation_callback == NULL)
941 list_for_each_safe(cur, tmp, &primary_channel->sc_list) {
942 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
944 primary_channel->sc_creation_callback(cur_channel);
948 void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
949 void (*sc_cr_cb)(struct vmbus_channel *new_sc))
951 primary_channel->sc_creation_callback = sc_cr_cb;
953 EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
955 bool vmbus_are_subchannels_present(struct vmbus_channel *primary)
959 ret = !list_empty(&primary->sc_list);
963 * Invoke the callback on sub-channel creation.
964 * This will present a uniform interface to the
967 invoke_sc_cb(primary);
972 EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present);